The objective of this project is to develop and apply nuclear magnetic resonance for elucidating molecular structures and for studying the interactions within and between molecules in making contributions to the solution of various chemical problems. NMR spectroscopy has been used: 1) to study the interaction between the volatile anaesthetic halothane and rat brain tissue. Results of 19F NMR data suggest that anesthetics interact nonspecifically with brain tissue and do not support the concept of the existence of an unique, saturable anaesthetic site for halothane in brain; 2) to elucidate the structures of major nucleoside adducts formed from adenine, guanine and cytosine bases of DNA and the optically active bay-region epoxides derived from polycyclic aromatic hydrocarbons; and 3) to study the mechanism of glycosidic bond cleavage of nucleosides and in particular, the reverse reaction by purine nucleoside phosphorylase.